The Republican Party will need to pick up ten seats to take control of the Senate in tonight's election, and even if they perform well, it will be a long shot. The GOP is virtually guaranteed to turn blue seats in Arkansas, North Dakota, and Indiana red, but 59 of the 100 sitting senators currently caucus with the Democrats, and a majority of that size is a significant buffer against a Republican takeover of the upper house. Nonetheless, if the political winds should blow the right way, the Senate could change hands tonight. Following are ten races to keep an eye on:

01. West Virginia: Open, previously held by Democrat Carte Goodwin, who filled the vacancy left by Robert C. Byrd's death.

If Republican John Raese picks this one up, count it as a sign the GOP has a shot at taking the Senate. The Democratic candidate Joe Manchin is the state's popular governor, and his campaign has run hard to the right and against Barack Obama, who is unpopular in the Mountain State. Manchin's polling numbers have been inching up, and he's favoured to win this one. If Raese takes it, Democrats will be nervously watching outcomes in the Western states.

02. Kentucky: Open, previously held by Republican Jim Bunning

The GOP nominee Rand Paul attracted a lot of attention when he won the nomination over party favourite Trey Grayson, and many predicted his strident libertarian views might cost the Republicans a safe seat. Democrat Jack Conway isn't entirely out of contention, but Paul is in the lead, and it would be an upset if he were to lose. If he does win, the Tea Party movement will be celebrating: Paul's nomination was a significant victory for the right wing uprising, and he's not been shy about expressing his approval of them. Voting in Kentucky closes at 6 p.m. EST (9 a.m. Sydney time), so this could be one of the first results reported of the night.

03. Pennsylvania: Open, previously held by Democrat Arlen Specter

Democrats rejoiced when veteran Republican moderate Arlen Specter switched his allegiance last year, giving the Dems a 60 seat, supposedly filibuster-proof, majority. Pennsylvania voters weren't as impressed; they nominated Joe Sestak in the primary and ended Specter's 30 year long Senate career. The Republican candidate, Pat Toomey, will probably turn the briefly blue seat red once again, but some recent polls have been showing Sestak gaining on his lead. Optimistic Democrats might recall that Sestak ran an effective campaign in the primary, which saw him make up a lot of ground in the few days before the election. Might he repeat that performance in the general?

04. Delaware: Open, previously held by Democrat Ted Kaufman, who filled the vacancy left by Joe Biden

There's little doubt about the result of this one; if Democrat Chris Coons can't beat the much derided Christine O'Donnell, the party might as well hand over the keys to the Republicans and try not to let the door hit them on the way out. But it's worth watching to work out how much of the vote O'Donnell will gain from her notoriety, and how Republicans will react to the Tea Party costing them a once certain pick-up. If the margin is closer than comfortable, expect a bad night for the Dems.

05. Illinois: Open, currently held by Roland Burris, who filled the vacancy left by Barack Obama

This is a tight race, and a point of pride for Democrats. An off-year rout is bad enough, but it would be even more demoralising to lose the seat recently held by the current president. Both major party candidates have experienced hiccups: Republican Mark Kirk has been accused of fudging some details of his military record, while Democrat Alexi Giannoulias has some unfortunate connections to an Illinois bank that collapsed due to some bad loans. If the Republicans don't win this one, they can't expect to win the Senate.

06. Colorado: Currently held by Democrat Michael Bennet, who replaced Ken Salazar on his appointment to Secretary of the Interior

Colorado was friendly territory for Democrats in 2008, and Obama's victory looked like the vanguard of a new Western progressivism. To some extent, Democrats are bucking the trend in Colorado, where the party's gubernatorial candidate John Hickenlooper has a strong lead over the conservative American Constitution Party candidate, one-time Republican Tom Tancredo. (The actual Republican nominee, Dan Maes, is a practically non-existent force.) Bennet will hope to benefit from Hickenlooper's popularity, and though Republican Ken Buck is the slight favourite, this one could go either way.

07. Nevada: Currently held by Democrat Harry Reid.

In Nevada, voters have the option of actually selecting "None of the above" on their ballot. Don't be surprised if a fair few take that choice; Nevadans are not happy with anyone on offer. The wildly unpopular Senate Majority Leader Harry Reid is as disliked in his home state as he is everywhere else, and given Nevada's wave of housing foreclosures and 14.2 per cent unemployment rate, this should be the tough campaign that even this tough campaigner can't win. But Republicans nominated the Tea Party-backed ultra-conservative Sharron Angle, who, among other things, opposes the Medicare, the Department of Education, and Social Security, and thinks Sharia law has taken over cities in Michigan and Texas. And yet, she may actually win this thing.

08. Washington: Currently held by Democrat Patty Murray.

I'll be paying close attention to this one, and not just because it's my home state here in America. If Republicans have a good night and win all the toss-ups in play, Washington will be one of the seats they'll need to gain control of the Senate. Incumbent Democrat Patty Murray is seeking a fourth term, and polls can't decide whether she or her Republican challenger Dino Rossi is in the lead. If the Senate does depend on the Evergreen state, its balance might not be decided tonight. Washingtonians vote exclusively by mail in all but one county, and ballots postmarked as recently as today will be counted. My gut tells me Murray will win this one, though my outlook might be skewed from my base in the state's liberal bastion of Seattle.

09. California: Currently held by Democrat Barbara Boxer.

Another seat that, like Washington, should be solidly Democratic, but Republicans hope to pick up in a favourable year like this one. It's another gain the GOP will have to make if it is to take the Senate. Carly Fiorina, the Republican candidate, is the former C.E.O. of Hewlett-Packard, and she's been criticised for laying off workers under her watch. While she's perhaps not been as strong a candidate as the Republican Party might have hoped, she still has a chance of beating a Democrat who should not be having to fight this hard to keep her seat.

Speaking of Carly Fiorina, if you haven't seen her "Demon Sheep" commercial from her primary campaign, you owe it to yourself to take a look.

10. Alaska: Currently held by write-in candidate Lisa Murkowski

If you were hoping to get to bed early, nice try. Alaska has turned what should have been a bland Republican victory into a bizarre three-way contest that will probably take days to resolve. Sitting Senator Lisa Murkowski was defeated by the Sarah Palin-backed Joe Miller in the Republican primary, and rather than give up her seat without a fight, Murkowski has decided to run as a write-in candidate. The only person to ever win a Senate race this way is former South Carolinian Strom Thurmond, in 1954, but Murkowski actually could become the second. Her biggest hurdle is getting voters to accurately spell "Murkowski" on their ballots, and we can be sure a close race will result in days of scrutiny and challenges over what exactly should count as a vote for Murkowski. With Republicans split between Miller and Murkowski, the low-profile Democratic nominee Scott McAdams might end up the winner. Since no one has much of an idea about how to poll a three-way race that includes a serious write-in candidate with a long surname, who knows how this one will turn out?

Elsewhere: There's probably not much point paying attention to Democrat Russ Feingold's almost certain loss in Wisconsin, and, unless you're a pro-wrestling fan hoping for an upset, don't spend too much time on Connecticut Republican and former WWE CEO Linda McMahon. But just for the fun of it, you might want to check on South Carolina Democrat Alvin Greene. Not to see if he beats Republican incumbent Jim DeMint, but to see if his share of the vote breaks double figures.